It depends what is meant by "economy". The word tends to be used in a narrow way these days. First, Afghanistan and Iraq are very different cases in terms of infrastructure, mostly because of Iraq's long history as a key trading region and its rapid industrialisation and further urbanisation during the second half of the 20th Century. Second, one doesn't need a state to have an economy. Even subsistence is an "economy". There may not be an economy in the sense of late modern economic management, but that doesn't mean there isn't an economy in the sense of accumulation, commodity production, markets, etc. Immanent, spontaneous market forces --- and the absence of sanctions --- will inevitably cause a boom in oil production in Iraq, and in Afghanistan there is increased opium production.
I think the big difference between -- for argument's sake --- Europe/Japan after 1945 and Iraq in 2003 is that Truman was a New Deal Democrat who acknowledged the role of the state in capitalist development, whereas the near-mystical faith of neo-liberals and neo-conservatives in laissez faire means that --- even from their point of view --- the "wrong" kind of development will occur in Afghanistan and Iraq, laying the groundwork for future local despots in those countries.